Made of resin-infused fiberglass for durability and breaking strengths in excess of 20,000 lb, DuraFiber™ Lids fit most ribbed PVC and HDPE riser pipe. Units feature flat-style flange, allowing flush-to-grade installation; cored centering ring, providing snug fit; and urethane gasket to help ensure watertight seal. Available in 24 and 30 in. diameters, DuraFiber Lids have non-skid surface with customizable center insert, along with molded-in Caution statement.